1. Field of Invention
This invention relates relates to a dental desk unit adapted to keep materials and tools used by the dentist at a temperature most suited to their use.
2. Prior Art
The need for keeping certain dental cements or filling material cooled to prevent premature setup is well recognized in the art, and suitable devices have been proposed for this purpose, as may be seen in U.S. Pat. Nos. 3,230,723 and 3,712,072, both of which utilize the well-known Peltier effect to obtain the desired cooling. Thermoelectric units of the Peltier type are well-known in the art. They comprise surfaces bonded together in such a way that, when a direct current is impressed on the element, one of the surfaces becomes hot, and the other surface becomes cold. In the devices of the references, the cold surface is utilized to provide the cooling of the device, and the heat generated by the hot surface is dissipated by a fan blowing on fins or other heat-radiating configurations. From the need for dissipating the heat with a fan, it is evident that the amount of heat generated is considerable, and is considered a disadvantage.
It has been proposed before to construct devices utilizing thermoelectric elements of the Peltier type, which utilize both the heat and cooling effect of the element. Such utilization is seen in U.S. Pat. Nos. 2,943,452 and 3,408,481. These devices, apart from their size and cumbersomeness, are not adapted for use as desk units in dentist's offices. They utilize closed compartments to conserve heat and to obtain as much cooling as possible, whereas these ends are not desirable in a dental desk unit, and without them, the references have no way of adequately balancing the heat and cooling obtained by the thermoelectric element.
U.S Pat. No. 3,808,825 discloses a device which purportedly accomplishes both cooling and heating by means of a thermoelectric element. Aside from the fact that the device is of questionable operativeness, because of the character of thermoelectric module, the two cups are of similar size, which means that the hot one would become extremely hot, and therefore be unsuitable for dental purposes. Moreover, the thermoelectric units are so constructed as to require cups of special shape, and therefore would have limited utility or none at all, if such specially shaped cups were not available.